Diagnostic use of a plurality of electrical battery parameters

ABSTRACT

In at least one embodiment, a power management module measures different observable quantities of a battery, such as terminal voltage or current, and measures a voltage response of the battery based upon the measurements. The measured voltage response of the battery is compared to a plurality of reference voltage responses, which may be determined for authentic batteries, for example. If the measured voltage response corresponds to each of the reference voltage responses, the battery is authenticated for use with an electronic device. If necessary, additional voltage responses may be measured and compared against corresponding reference voltage responses until the battery is authenticated by a sufficient number of corresponding responses. A relative condition of the battery, such as an age or state of health, may also be estimated based on the measured voltage response of the battery.

FIELD

The embodiments described herein relate generally to mobile deviceshaving a battery and, more particularly, to diagnostic use of physicaland electrical battery parameters on mobile devices.

BACKGROUND

Wireless communication devices, personal data assistants and other typesof mobile devices are commonly powered by internal power supplies, suchas an internal battery or battery pack. The internal battery pack may bean assembly of one or more battery cells or battery modules that,depending on different factors, are capable of delivering a certainamount of charge to the mobile device in each given charging-dischargingcycle. Different battery packs are designed to have different chargecapacities, terminal voltages, charging characteristics, and dischargingcharacteristics. Battery packs may be removable from the mobile device,for example, using a battery pack compartment in which the battery ishoused using a securable cover. Alternatively, some battery packs may be“non-removable”, in the sense that ready access to the battery packcompartment is more difficult to gain.

Many battery packs incorporate a battery ID resistor through which themobile device may ascertain at least one of the type or model of a givenbattery pack. Typically, the battery ID resistor is connected betweentwo external pins of the battery pack and has a characteristicresistance value that is allocated to the given battery model. Aprocessor in the mobile device then measures the resistance of thebattery ID resistor and determines one or both of the type andmanufacture of the battery by comparing the measured resistance valueagainst known values. If a match is found, the battery is identified.

More recently with the introduction of so-called “smart batteries”,which may have an integrated battery processor or some other processingelements or circuitry in certain implementations, and in some casesstorage memory, a main processor of the mobile device is able toidentify different battery models by initiating a communication protocolwith the battery processor. By way of example, according to thecommunication protocol, the main processor of the mobile device and abattery processor of the smart battery may be able to exchange differenttypes of data and other information. In some cases, the batteryprocessor transmits a battery ID value stored in the battery memory tothe main processor to indicate the given battery model. Additionalinformation relating to the charge capacity, charging characteristicsand discharging characteristics of the battery may also be communicatedto the main processor, for use by the main processor to controloperation of the battery.

In addition to identifying a type or model of the battery, thecommunication protocol executed between the main processor and thebattery processor may be used to authenticate the source of the smartbattery. Some batteries may be manufactured by authorized sources, whileother batteries may originate from third-party, non-authorized sources.Still other batteries may be counterfeit (i.e., passed off as being froman authorized source when they have not in fact originated from theauthorized source). To authenticate the mobile device battery as beingfrom an authorized source, the main processor may generate and send achallenge message to the battery processor. If the battery processor isable to generate the correct response message, for example by processingthe challenge message with a cryptographic algorithm or other piece ofcryptographic data, such as a cryptographic key, the battery isauthenticated for use with the mobile device. However, an incorrectresponse message could indicate that the battery is not authentic or iscounterfeit. Data integrity checks may also be utilized to ensure thatan incorrect response message is due to the battery being inauthenticand not a data error during transmission.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the described embodiments and to show moreclearly how they may be carried into effect, reference will now be made,by way of example, to the accompanying drawings in which:

FIG. 1 is a block diagram of an example embodiment of a mobilecommunication device;

FIG. 2 is a block diagram of an example embodiment of a communicationsubsystem of the mobile communication device of FIG. 1;

FIG. 3 is a block diagram of an example embodiment of a node of awireless network with which the mobile communication device of FIG. 1may communicate;

FIG. 4 is a block diagram of an example embodiment of a battery used tosupply power to the mobile communications device of FIG. 1;

FIG. 5A is a graph showing a relationship between cell voltage andbattery capacity at different points in the life cycle of an authenticbattery;

FIG. 5B is a graph showing a relationship between cell voltage andbattery capacity at different points in the life cycle of an inauthenticbattery;

FIG. 6A is a graph showing a relationship between charge differentialand battery voltage for both authentic and inauthentic batteries;

FIG. 6B is a graph showing a relationship between charge differentialand battery voltage for both authentic and inauthentic batteries thathave been heavily cycled;

FIG. 7 is a graph showing a relationship between battery voltage at peakcharge differential and charge time for both authentic and inauthenticbatteries;

FIG. 8 is a graph showing a relationship between battery voltage at peakcharge differential and charge capacity for both authentic andinauthentic batteries over the life cycle of the battery;

FIG. 9A is a graph showing a transient response of a fresh battery dueto pulsed charging or discharging;

FIG. 9B is a graph showing a transient response of a heavily cycledbattery due to pulsed charging or discharging;

FIG. 10 is a schematic diagram illustrating the internal windingstructure of a battery module included in the battery shown in FIG. 3;

FIG. 11 is a network model for the internal winding structure of thebattery module shown in FIG. 10;

FIG. 12A is a graph plotting the real and imaginary components ofbattery impedance for a new battery at different frequencies;

FIG. 12B is a graph plotting the magnitude and phase of batteryimpedance as a function of frequency for a new battery;

FIG. 12C is a graph plotting the real and imaginary components ofbattery impedance for a heavily cycled battery at different frequencies;

FIG. 12D is a graph plotting the magnitude and phase of batteryimpedance as a function of frequency for a heavily cycled battery;

FIG. 13A is a front perspective view of an example embodiment of themobile device shown in FIG. 1 with several antennas indicated;

FIG. 13B is a rear perspective view of the example embodiment of themobile device shown in FIG. 1 with the mobile device battery and severalantennas indicated;

FIG. 14 is a flow chart illustrating a method of authenticating abattery in accordance with at least one embodiment; and

FIG. 15 is a flow chart illustrating a method of determining an estimateof the relative condition of a battery in accordance with at least oneembodiment.

DESCRIPTION OF EMBODIMENTS

Being able to identify one or both of the type and model of a battery,as well as to authenticate the source of the battery, may be useful forone or more reasons. As one example, rechargeable batteries shouldgenerally be charged to the proper charge capacity and at the propercharging rate. If the battery is overcharged, the battery and the mobiledevice in which the battery is inserted may both become damaged. Thissituation becomes more common with increasing numbers of third-partyunauthorized or counterfeit batteries made available on the market. Theproper charge rate and capacity of an authorized battery may beascertained once the battery is properly identified and authenticated.

Third-party unauthorized or counterfeit battery packs (also referred toherein more generally as inauthentic battery packs) may not generallyhave the same charge capacity, durability or lifespan of an authenticbattery pack originating from an authorized manufacturing source.Inauthentic battery packs may be deficient in other ways as well, forexample, by not having the required safety protection circuitry.Charging methods employed by the mobile device that were designed forauthentic battery packs may be incompatible with inauthentic batterypacks. Any of these differences in an inauthentic battery pack may causethe battery pack to fail during charging or through normal usage.

For battery packs that are identifiable using battery ID resistors, itmay be possible to read the resistance value of the battery ID resistorand manufacture a third-party unauthorized or counterfeit battery packhaving the same resistance value. From the standpoint of the mobiledevice, authentic batteries then become indistinguishable from thethird-party unauthorized or counterfeit battery packs in terms of thebattery ID resistor. The mobile device may then unintentionallyauthenticate a third-party unauthorized or counterfeit battery for usewith the mobile device, even though the battery is not, in fact,authentic.

Use of smart battery technology somewhat enhances battery authenticationand security. The processor integrated into the battery pack allows fora cryptographic authentication protocol to be implemented in the mobiledevice, for example, including challenge-response messages or public andprivate cryptographic keys. However, cryptographic authenticationprotocols may still not provide absolute security. For example, it maystill be possible for a third party interested in manufacturing anunauthorized or counterfeit battery to intercept some piece ofcryptographic data, such as a private key, which then enables thethird-party to break the cryptographic authentication protocol.Thereafter, the inauthentic battery packs may again falsely appear tothe mobile device as authentic battery packs.

As an alternative, or in addition to cryptographic authenticationprocesses, the mobile device processor may make diagnostic use ofvarious physical and electrical parameters of a battery pack to enhancebattery authentication and security. Due to different physicalgeometries and fabrication processes, different battery packs willgenerally exhibit different characteristic responses during certainparts of the charging cycle, discharging cycle or both, as well as inresponse to different current demands. The characteristic responses mayinclude electromagnetic or electrical responses or both. For example,the size and layout of the battery pack can contribute to the electricaland physical characteristics of the battery pack. The internalelectrochemistry and structure of the battery cells or battery modules,such as a configuration of the battery windings, can also eachcontribute to the electrical and physical characteristics of the batterypack. Accordingly, under certain conditions, authorized battery packsproduced by an authorized manufacturer will respond generallydifferently, as well as characteristically, in comparison to inauthenticbattery packs.

Even if an inauthentic battery pack can be falsely authenticated by themain processor by presenting the correct battery ID resistor or responsemessage as part of a cryptographic authentication protocol, thelikelihood of the inauthentic battery pack exhibiting the samecharacteristic responses as an authentic battery pack in each of avariety of different charge and discharge conditions is extremely low.An average production run of a certain battery model might be, forexample, between about 1 to 2 years, which places very tight timeconstraints on the third-party to match the manufacturing process of anauthentic battery within the lifetime of the battery model. Third-partyunauthorized and counterfeit batteries are also commonly manufacturedusing less expensive materials and processes than are used for authenticbatteries. These and other factors make the likelihood of the authenticand inauthentic batteries having matched responses in each of thedifferent conditions close to, if not, zero.

Even authentic batteries originating from the same source will not haveidentical geometries or perform identically under all conditions. Forexample, some inherent tolerance is typical even for tightly controlledmanufacturing processes. Small deviations in physical battery geometrymay translate into slightly different responses to being charged anddischarged. Accordingly, the response of a given battery may bedetermined to match a reference response for authentic batteries of thatmodel when there is a correlation between actual and expectedperformance within some acceptable range of values. In some cases, acriterion of matching or correlation may be used for making thedetermination. The criterion and the range of values may each bedefined.

To increase the robustness of a security and authentication protocolbased around battery physical and electrical properties, the degree ofcorrelation between actual and reference response required for apositive match may be lowered, while the number of different testconditions may be increased. As noted above, the likelihood of athird-party unauthorized or counterfeit battery having a matchedresponse in each of the variety of different conditions may be close tozero. An unidentified battery may therefore be tested under a sufficientnumber of different charging and discharging conditions until it can beconcluded with an acceptable level of confidence that the battery isauthentic. This authentication considers the physical and electricalproperties of the battery. Use of battery ID resistors or cryptographicalgorithms, which are each comparatively simpler to replicate ininauthentic batteries than are physical and electrical properties, arenot required.

In one broad aspect, there is provided an electronic device comprising:an interface for receiving a battery comprising a battery module forsupplying power to the electronic device; and a power management modulecoupled to the battery and configured to: measure a voltage response ofthe battery due to current flow in the battery module; compare themeasured voltage response of the battery to each of a plurality ofreference voltage responses; and if the measured voltage responsecorresponds to each of the plurality of reference voltage responses,authenticate the battery for use with the electronic device.

In another broad aspect, the device further comprises the battery.

In another broad aspect, the device comprises a mobile communicationdevice.

In another broad aspect, each of the plurality of reference voltageresponses comprises a reference voltage response of an authenticbattery.

In another broad aspect, each of the reference voltage responsescorresponding to a different relative condition of the authenticbattery, and the power management module is further configured todetermine a relative condition of the battery by comparing the measuredvoltage response with each of the plurality of reference voltageresponses.

In another broad aspect, the relative condition of the battery comprisesat least one of an age or state of health of the battery.

In another broad aspect, the power management module is configured to:measure a plurality of voltage responses of the battery due to currentflow in the battery module; compare each of the measured plurality ofvoltage responses of the battery with a corresponding one of theplurality of reference voltage responses; and if a minimum number of themeasured plurality of voltage responses corresponds to a thresholdnumber of the plurality of reference voltage responses, authenticate thebattery for use with the electronic device.

In another broad aspect, the power management module is configured tomeasure the voltage response of the battery based on a plurality of ACvoltages measured across the battery module, each measured AC voltagemeasured for a corresponding AC excitation current of a differentfrequency supplied to the battery module.

In another broad aspect, the power management module is configured tomeasure the voltage response of the battery based on a voltage slumpmeasured across the battery module during pulsed discharging of thebattery module.

In another broad aspect, the power management module is configured tomeasure the voltage response of the battery based on a chargedifferential relation of the battery module, the charge differentialrelation representing a rate of change of a charge capacity of thebattery module with respect to a terminal voltage of the battery module.

In another broad aspect, the power management module is configured tomeasure the voltage response of the battery based on a charge capacityrelation of the battery module, the charge capacity relationrepresenting stored charge in the battery module as a function of aterminal voltage of the battery module.

In another broad aspect, there is provided a method for authenticating abattery for use with an electronic device, the battery comprising abattery module for supplying power to the electronic device, the methodcomprising: measuring a voltage response of the battery due to currentflow in the battery module; comparing the measured voltage response ofthe battery to each of a plurality of reference voltage responses; andif the measured voltage response corresponds to each of the plurality ofreference voltage responses, authenticating the battery for use with theelectronic device.

In another broad aspect, there is provided a power management module foran electronic device supplied with power from a battery comprising abattery module, the power management module comprising a processor andmemory coupled to the processor storing instructions when executed forprogramming the processor, the instructions comprising: measuring avoltage response of the battery due to current flow in the batterymodule; comparing the measured voltage response of the battery to eachof a plurality of reference voltage responses; and if the measuredvoltage response corresponds to each of the plurality of referencevoltage responses, authenticating the battery for use with theelectronic device.

The embodiments described herein may, for example, generally haveapplicability in the field of data communication for mobilecommunication devices that use a “smart battery”, which is a batterypack that is typically implemented with an embedded battery processorand other related circuitry to allow communication between the batteryand the mobile device.

The embodiments described herein may primarily reference a mobilewireless communication device that has a main processor and is poweredby a smart battery having a battery processor, a battery interface andrelated electronics. The battery interface is used for communicationwith one or more processors of the mobile device, such as a mainprocessor or a power management module of the mobile device, as will bedescribed in more detail below. However, it should be understood thatthe structure and functionality of the embodiments described herein mayalso be applied to a battery charger that charges a smart battery. Stillother embodiments described herein may relate to battery packs that haveno embedded processor or related electronics, i.e. a “passive” batteryback.

The described embodiments generally relate to authenticating one or morebatteries used for supplying power to an electronic device, which insome embodiments, may comprise a mobile communication device. A mobilecommunication device may also be referred to as a mobile device. In thecase where the device is a mobile communication device, it may comprisea two-way communication device with advanced data communicationcapabilities having the capability to communicate in a wireless or wiredfashion with other computing devices including other mobilecommunication devices. The mobile device may communicate with otherdevices through a network of transceiver stations. The mobile device mayalso include the capability for voice communications. However, dependingon the functionality provided by the mobile device and the structure ofthe mobile device, it may be referred to as a data messaging device, acellular telephone with data messaging capabilities, a wirelessorganizer, a wireless Internet appliance, a personal digital assistant,a smart phone, a handheld wireless communication device (with or withouttelephony capabilities), a wirelessly enabled notebook computer and thelike.

To aid in understanding the general structure and operation of themobile device with which the described embodiments operate, referencewill be made to FIGS. 1 to 3. However, it should be understood thatembodiments of the mobile device are not limited only to those which arespecifically described herein.

Referring first to FIG. 1, shown therein is a block diagram of a mobiledevice 100 in one example implementation. The mobile device 100comprises a number of components, the controlling component being a mainprocessor 102, which controls the overall operation of mobile device100. Communication functions, including data and voice communications,are performed through a communication subsystem 104. The communicationsubsystem 104 receives messages from and sends messages to a wirelessnetwork 200. In some implementations of the mobile device 100, thecommunication subsystem 104 is configured in accordance with the GlobalSystem for Mobile Communication (GSM) and General Packet Radio Services(GPRS) standards. The GSM/GPRS wireless network is used worldwide. Otherstandards that may be used include the Enhanced Data GSM Environment(EDGE), Universal Mobile Telecommunications Service (UMTS), CodeDivision Multiple Access (CDMA), Intelligent Digital Enhanced Network(iDEN™), and Long Term Evolution (LTE) standards. New standards arestill being defined, and it will be understood by persons skilled in theart that the embodiments described herein may use any other suitablestandards that are developed in the future. The wireless link connectingthe communication subsystem 104 with the wireless network 200 representsone or more different Radio Frequency (RF) channels, operating accordingto defined protocols specified for GSM/GPRS communications. With newernetwork protocols, these channels are capable of supporting both circuitswitched voice communications and packet switched data communications.

Although the wireless network 200 associated with the mobile device 100is a GSM/GPRS wireless network in some implementations, other wirelessnetworks may also be associated with the mobile device 100 in otherimplementations. The different types of wireless networks that may beemployed include, for example, data-centric wireless networks,voice-centric wireless networks, and dual-mode networks that may supportboth voice and data communications over the same physical base stations.Combined dual-mode networks include, but are not limited to, CodeDivision Multiple Access (CDMA) or CDMA2000 networks, iDEN networks,GSM/GPRS networks (as mentioned above), and future third-generation (3G)networks like EDGE and UMTS. Some other examples of data-centricnetworks include WiFi 802.11, Mobitex™ and DataTAC™ networkcommunication systems. Examples of other voice-centric data networksinclude Personal Communication Systems (PCS) networks like GSM and TimeDivision Multiple Access (TDMA) systems.

The main processor 102 also interacts with additional subsystems such asa Random Access Memory (RAM) 106, a device memory 108, a display 110, anauxiliary input/output (I/O) subsystem 112, a data port 114, a keyboard116, a speaker 118, a microphone 120, a short-range communicationsubsystem 122, and other device subsystems 124.

Some of the subsystems of the mobile device 100 performcommunication-related functions, whereas other subsystems may provide“resident” or on-device functions. By way of example, the display 110and the keyboard 116 may be used for both communication-relatedfunctions, such as entering a text message for transmission over thenetwork 200, and device-resident functions such as a calculator or tasklist. Operating system software used by the main processor 102 istypically stored in a persistent store such as the device memory 108,which may alternatively be a read-only memory (ROM) or similar storageelement (not shown). In some cases, the device memory 108 may be flashmemory. Those skilled in the art will appreciate that the operatingsystem, specific device applications, or parts thereof, may betemporarily loaded into a volatile store such as the RAM 106.

The mobile device 100 may send and receive communication signals overthe wireless network 200 after required network registration oractivation procedures have been completed. Network access is associatedwith a subscriber or user of the mobile device 100. To identify asubscriber, the mobile device 100 may require a SIM/RUIM card 126 (i.e.Subscriber Identity Module or a Removable User Identity Module) to beinserted into a SIM/RUIM interface 128 in order to communicate with anetwork. Accordingly, the SIM card/RUIM 126 and the SIM/RUIM interface128 are entirely optional.

The SIM card or RUIM 126 is one type of a conventional “smart card” thatmay be used to identify a subscriber of the mobile device 100 and topersonalize the mobile device 100, among other things. Without the SIMcard 126, the mobile device 100 is not fully operational forcommunication with the wireless network 200. By inserting the SIMcard/RUIM 126 into the SIM/RUIM interface 128, a subscriber may accessall subscribed services. Services may include: web browsing andmessaging such as e-mail, voice mail, Short Message Service (SMS), andMultimedia Messaging Services (MMS). More advanced services may include:point of sale, field service and sales force automation. The SIMcard/RUIM 126 includes a processor and memory for storing information.Once the SIM card/RUIM 126 is inserted into the SIM/RUIM interface 128,the SIM card/RUIM 126 is coupled to the main processor 102. In order toidentify the subscriber, the SIM card/RUIM 126 contains some userparameters such as an International Mobile Subscriber Identity (IMSI).An advantage of using the SIM card/RUIM 126 is that a subscriber is notnecessarily bound by any single physical mobile device. The SIMcard/RUIM 126 may store additional subscriber information for a mobiledevice as well, including datebook (or calendar) information and recentcall information. Alternatively, user identification information mayalso be programmed into the device memory 108.

The mobile device 100 is a battery-powered device and may include abattery interface 132 for interfacing with a battery 130. In this case,the battery interface 132 is also coupled to a power management module134, which is used to authenticate the battery 130, but also to assistthe battery 130 in providing power to the mobile device 100. The mainprocessor 102 may also be coupled to the power management module 134 forsharing information. However, in alternative embodiments, the batteryinterface 132 may be provided by the battery 130.

In addition to operating system functions, the microprocessor 102enables execution of software applications 136 on the mobile device 100.The subset of software applications 136 that control basic deviceoperations, including data and voice communication applications, willnormally be installed on the mobile device 100 during manufacturing ofthe mobile device 100. The software applications 136 may include anemail program, a web browser, an attachment viewer, and the like.

The mobile device 100 may further include a device state module 138, anaddress book 140, a Personal Information Manager (PIM) 142, and othermodules 144. The device state module 138 may provide persistence, i.e.the device state module 138 ensures that important device data is storedin persistent memory, such as the device memory 108, so that the data isnot lost when the mobile device 100 is turned off or loses power. Theaddress book 140 may provide information for a list of contacts for theuser. For a given contact in the address book, the information mayinclude the name, phone number, work address and email address of thecontact, among other information. The other modules 144 may include aconfiguration module (not shown) as well as other modules that may beused in conjunction with the SIM/RUIM interface 128.

The PIM 142 has functionality for organizing and managing data items ofinterest to a subscriber, such as, but not limited to, e-mail, calendarevents, voice mails, appointments, and task items. A PIM application hasthe ability to send and receive data items via the wireless network 200.PIM data items may be seamlessly integrated, synchronized, and updatedvia the wireless network 200 with the mobile device subscriber'scorresponding data items stored or otherwise associated with a hostcomputer system. This functionality creates a mirrored host computer onthe mobile device 100 with respect to such items. This may beparticularly advantageous when the host computer system is the mobiledevice subscriber's office computer system.

Additional applications may also be loaded onto the mobile device 100through at least one of the wireless network 200, the auxiliary I/Osubsystem 112, the data port 114, the short-range communicationssubsystem 122, or any other suitable device subsystem 124. Thisflexibility in application installation increases the functionality ofthe mobile device 100 and may provide enhanced on-device functions,communication-related functions, or both. For example, securecommunication applications may enable electronic commerce functions andother such financial transactions to be performed using the mobiledevice 100.

The data port 114 enables a subscriber to set preferences through anexternal device or software application and extends the capabilities ofthe mobile device 100 by providing for information or software downloadsto the mobile device 100 other than through a wireless communicationnetwork. The alternate download path may, for example, be used to loadan encryption key onto the mobile device 100 through a direct and thusreliable and trusted connection to provide secure device communication.

The data port 114 may be any suitable port that enables datacommunication between the mobile device 100 and another computingdevice. The data port may be a serial or a parallel port. In someinstances, the data port 114 may be a USB port that includes data linesfor data transfer and a supply line that may provide a charging currentto charge the mobile device 100.

The short-range communications subsystem 122 provides for communicationbetween the mobile device 100 and different systems or devices, withoutthe use of the wireless network 200. For example, the subsystem 122 mayinclude an infrared device and associated circuits and components forshort-range communication. Examples of short-range communicationstandards include those developed by the Infrared Data Association(IrDA), Bluetooth, RFID, NFC, and the 802.11 family of standardsdeveloped by IEEE.

In use, a received signal such as a text message, an e-mail message, orweb page download will be processed by the communication subsystem 104and input to the main processor 102. The main processor 102 will thenprocess the received signal for output to the display 110 oralternatively to the auxiliary I/O subsystem 112. A subscriber may alsocompose data items, such as e-mail messages, for example, using thekeyboard 116 in conjunction with the display 110 and possibly theauxiliary I/O subsystem 112. The auxiliary subsystem 112 may includedevices such as: a touch screen, mouse, track ball, infrared fingerprintdetector, or a roller wheel with dynamic button pressing capability. Thekeyboard 116 is preferably an alphanumeric keyboard and/ortelephone-type keypad. However, other types of keyboards may also beused. A composed item may be transmitted over the wireless network 200through the communication subsystem 104.

For voice communications, the overall operation of the mobile device 100is substantially similar, except that the received signals are output tothe speaker 118, and signals for transmission are generated by themicrophone 120. Alternative voice or audio I/O subsystems, such as avoice message recording subsystem, may also be implemented on the mobiledevice 100. Although voice or audio signal output is accomplishedprimarily through the speaker 118, the display 110 may also be used toprovide additional information such as the identity of a calling party,duration of a voice call, or other voice call related information.

Referring now to FIG. 2, a block diagram of an example embodiment of thecommunication subsystem component 104 of FIG. 1 is shown. Thecommunication subsystem 104 comprises a receiver 150 and a transmitter152, as well as associated components such as one or more embedded orinternal antenna elements 154, 156, Local Oscillators (LOs) 158, and acommunications processor 160 for wireless communication. Thecommunications processor 160 may be a Digital Signal Processor (DSP). Aswill be apparent to those skilled in the field of communications, theparticular design of the communication subsystem 104 may depend on thecommunication network with which the mobile device 100 is intended tooperate. Thus, it should be understood that the design illustrated inFIG. 2 serves only as an example.

Signals received by the antenna 154 through the wireless network 200 areinput to the receiver 150, which may perform such common receiverfunctions as signal amplification, frequency down conversion, filtering,channel selection, and analog-to-digital (ND) conversion. ND conversionof a received signal allows more complex communication functions such asdemodulation and decoding to be performed by the communicationsprocessor 160. In a similar manner, signals to be transmitted areprocessed, including modulation and encoding, by the communicationsprocessor 160. These processed signals are input to the transmitter 152for digital-to-analog (D/A) conversion, frequency up conversion,filtering, amplification and transmission over the wireless network 200via the antenna 156. The communications processor 160 not only processescommunication signals, but also provides for receiver and transmittercontrol. For example, the gains applied to communication signals in thereceiver 150 and transmitter 152 may be adaptively controlled throughautomatic gain control algorithms implemented in the communicationsprocessor 160.

The wireless link between the mobile device 100 and the wireless network200 may contain one or more different channels, typically different RFchannels, and associated protocols used between the mobile device 100and the wireless network 200. An RF channel is a limited resource thatshould be conserved, typically due to limits in overall bandwidth andbattery power of the mobile device 100.

When the mobile device 100 is fully operational, the transmitter 152 istypically keyed or turned on only when the transmitter 182 is sending tothe wireless network 200 and is otherwise turned off to conserveresources. Similarly, the receiver 150 is periodically turned off toconserve power until the receiver 180 is needed to receive signals orinformation (if at all) during designated time periods.

Referring now to FIG. 3, a block diagram of an example embodiment of anode of the wireless network 200 is shown as 202. In practice, thewireless network 200 comprises one or more nodes 202. The mobile device100 communicates with the node 202. In the exemplary implementation ofFIG. 3, the node 202 is configured in accordance with General PacketRadio Service (GPRS) and Global Systems for Mobile (GSM) technologies.The node 202 includes a base station controller (BSC) 204 with anassociated tower station 206, a Packet Control Unit (PCU) 208 added forGPRS support in GSM, a Mobile Switching Center (MSC) 210, a HomeLocation Register (HLR) 212, a Visitor Location Registry (VLR) 214, aServing GPRS Support Node (SGSN) 216, a Gateway GPRS Support Node (GGSN)218, and a Dynamic Host Configuration Protocol (DHCP) 220. This list ofcomponents is not meant to be an exhaustive list of the components ofevery node 202 within a GSM/GPRS network, but rather an illustrativelist of components that may be used in communications through thewireless network 200.

In a GSM network, the MSC 210 is coupled to the BSC 204 and to alandline network, such as a Public Switched Telephone Network (PSTN) 222to satisfy circuit switching requirements. The connection through PCU208, SGSN 216 and GGSN 218 to the public or private network (Internet)224 (also referred to generally as a shared network infrastructure)represents the data path for GPRS capable mobile devices. In a GSMnetwork extended with GPRS capabilities, the BSC 204 also contains aPacket Control Unit (PCU) 208 that connects to the SGSN 216 to controlsegmentation, radio channel allocation and to satisfy packet switchedrequirements. To track mobile device location and availability for bothcircuit switched and packet switched management, the HLR 212 is sharedbetween the MSC 210 and the SGSN 216. Access to the VLR 214 iscontrolled by the MSC 210.

The station 206 is a fixed transceiver station. The station 206 and BSC204 together form the fixed transceiver equipment. The fixed transceiverequipment provides wireless network coverage for a particular coveragearea commonly referred to as a “cell”. The fixed transceiver equipmenttransmits communication signals to and receives communication signalsfrom mobile devices within its cell via the station 206. The fixedtransceiver equipment normally performs such functions as modulation andpossibly encoding (e.g., encryption) of signals to be transmitted to themobile device 100 in accordance with particular communication protocolsand parameters, under control of its controller. The fixed transceiverequipment similarly demodulates and possibly decodes (e.g., decrypts),if necessary, any communication signals received from the mobile device100 within its cell. The communication protocols and parameters may varybetween different nodes. For example, one node may employ a differentmodulation scheme and operate at different frequencies than other nodes.

For all mobile devices 100 registered with a specific network, permanentconfiguration data such as a user profile is stored in the HLR 212. TheHLR 212 also contains location information for each registered mobiledevice and may be queried to determine the current location of a mobiledevice. The MSC 210 is responsible for a group of location areas andstores the data of the mobile devices currently in its area ofresponsibility in the VLR 214. Further, the VLR 214 also containsinformation on mobile devices that are visiting other networks. Theinformation in the VLR 214 includes part of the permanent mobile devicedata transmitted from the HLR 212 to the VLR 214 for faster access. Bymoving additional information from a remote HLR 212 node to the VLR 214,the amount of traffic between these nodes may be reduced so that voiceand data services may be provided with faster response times, while atthe same time using fewer computing resources.

The SGSN 216 and GGSN 218 are elements added for GPRS support, namelypacket switched data support, within GSM. The SGSN 216 and MSC 210 havesimilar responsibilities within the wireless network 200 by keepingtrack of the location of each mobile device 100. The SGSN 216 alsoperforms security functions and access control for data traffic on thewireless network 200. The GGSN 218 provides internetworking connectionswith external packet switched networks and connects to one or moreSGSN's 216 via an Internet Protocol (IP) backbone network operatedwithin the network 200. During normal operations, a given mobile device100 must perform a “GPRS Attach” to acquire an IP address and to accessdata services. This requirement is not present in circuit switched voicechannels as Integrated Services Digital Network (ISDN) addresses areused for routing incoming and outgoing calls. Currently, all GPRScapable networks use private, dynamically assigned IP addresses, thusrequiring the DHCP server 220 to be connected to the GGSN 218. There aremany mechanisms for dynamic IP assignment, including using a combinationof a Remote Authentication Dial-In User Service (RADIUS) server and DHCPserver. Once the GPRS Attach is complete, a logical connection isestablished from the mobile device 100, through the PCU 208, and theSGSN 216 to an Access Point Node (APN) within the GGSN 218. The APNrepresents a logical end of an IP tunnel that may either access directInternet compatible services or private network connections. The APNalso represents a security mechanism for the wireless network 200,insofar as each mobile device 100 is assigned to one or more APNs, andthe mobile devices 100 generally cannot exchange data without firstperforming a GPRS Attach to an APN that the mobile device 100 has beenauthorized to use. The APN may be considered to be similar to anInternet domain name such as “myconnection.wireless.com”.

Once the GPRS Attach is complete, a tunnel is created and all traffic isexchanged within standard IP packets using any protocol that may besupported in IP packets. This includes tunneling methods such as IP overIP as in the case with some IPSecurity (IPsec) connections used withVirtual Private

Networks (VPN). These tunnels are also referred to as Packet DataProtocol (PDP) contexts and there are a limited number of theseavailable in the wireless network 200. To maximize use of the PDPContexts, the wireless network 200 will run an idle timer for each PDPContext to determine if there is a lack of activity. When the mobiledevice 100 is not using the PDP Context allocated to the mobile device100, the PDP Context may be de-allocated and the IP address returned tothe IP address pool managed by the DHCP server 220.

Referring now to FIG. 4, shown therein is a block diagram of an exampleembodiment of the battery 130 that may be used in a device such as themobile device 100. The battery 130 includes a battery processor 252, abattery memory 254, switching and protection circuitry 258, measurementcircuitry 260, including an analog to digital converter (not shown), anda battery module 262. The battery 130 is connected to the main processor102 and to the power management module 134 through the battery interface132.

In one example embodiment, the battery module 262 includes one or morebattery windings. More generally, the battery module 262 may include oneor more battery cells or charge storage devices, which are generallyrechargeable over the life span of the battery 130, although the chargecapacity of the battery windings may slowly deteriorate over time. Thebattery windings or cells may be made using nickel-cadmium, nickel-metalhydride or lithium-ion processes, or other suitable composite materialsand the like. Further details of battery windings are provided belowwith reference to FIG. 10.

The battery module 262 provides supply power to the battery processor252, which then provides the supply power to the main processor 102 viathe battery interface 132, using suitable connections, such as via asystem power bus. The battery interface 132 is shown in FIG. 4 externalto the battery 130, but in alternative embodiments may be internal tothe battery 130, or partially internal and partially external to thebattery 130.

The battery processor 252 controls the operation of the battery 130 andmay communicate with the main processor 102 via the battery interface132. The battery processor 252 may include, for example, registers,stacks, counters, a watchdog timer, and other components (not shown)that are commonly used by a processor. The battery processor 252 mayalso include a clock (not shown). The battery 130 may store informationin the battery memory 254. The battery memory 254 may comprise acombination of volatile and non-volatile memory. In someimplementations, a single General Purpose Input/Output (GPIO) pin on thebattery processor 252 may be connected to the main processor 102 acrossthe battery interface 132 to receive instructions from the mainprocessor 102 and to provide data to the main processor 102.

The measurement circuitry 260 may be used by the battery 130 to readcertain data related to the operation of the battery module 262, such asbattery current, battery voltage, battery temperature and the like.These measurements may be used to obtain an estimate of the amount ofcharge capacity remaining in the battery module 262. To perform thesemeasurements, the measurement circuitry 260 includes an analog todigital converter (ADC) (not shown). The measurement circuitry 260 maybe optional, since in alternative embodiments, the mobile device 100rather than the battery 130, may include circuitry for performing thefunctionality of the measurement circuitry 260.

The switching and protection circuitry 258 may be used to protect thebattery 130. The switching and protection circuitry 258 may act like acircuit breaker and may be activated by the battery processor 252 or themain processor 102 under certain situations to prevent the battery 130from being damaged during use. For instance, the switching andprotection circuitry 258 may include a thermal breaker to disable thebattery 130 when the temperature of the battery module 262 becomes toohigh. The thermal breaker may also disconnect the battery 130 under highcurrent loads if other protection circuitry fails. The switching andprotection circuitry 258 may also protect against short circuits,under-voltage conditions, over-voltage charging, reverse polarity beingapplied to the battery 130, etc. Accordingly, the switching andprotection circuitry 258 may also be used during the charging,discharging or pre-charging of the battery module 262, as well as forbattery cell balancing. Additional protection circuitry may also beincluded in the battery interface 132 in some embodiments.

The battery 130 is also connected to the power management module 134 ofthe mobile device 100 via the battery interface 132. The powermanagement module 134 communicates with the battery processor 252 totake measurements of different operating characteristics of the batterymodule 262 using the measurement circuitry 260. For example, the batterycurrent (charging or discharging), terminal voltage and temperature ofthe battery module 262 may be measured.

The power management module 134 may request that various measurements ofthe battery module 262 be taken under specific conditions. In somecases, the specific conditions arise during normal operation of thebattery 130, such as different operations performed by the mainprocessor 102 or the communication subsystem 104 (FIG. 1). As anon-limiting example, the power management module 134 may take batterymeasurements during an incoming GSM pulse received into thecommunication subsystem 104, when there is a substantial current demandon the battery module 262. The power management module 134 may alsorequest that measurements of the battery module 262 be taken duringcharging of the battery module 262, or alternatively during power on ofthe mobile device 100.

In some cases, rather than taking measurements of the battery module 262for naturally occurring conditions during operation of the mobile device100 (e.g., an incoming GSM pulse), the power management module 134 mayinstead temporarily interrupt normal operation of the mobile device 100in order to subject the battery module 262 to artificially createdcharging or discharging conditions. For example, the power managementmodule 134 may request a certain current draw (e.g., 1 C, 2 C, 0.5 C,etc.) on the battery module 262, and then measure the response of thebattery module 262 to the requested current draw. Alternatively, thepower management module 134 may charge the battery module 262 with acertain charge current, such as those noted above. As will beappreciated, “1 C” represents the magnitude of a current that wouldfully charge or drain the battery module 162 in one hour, and a “2 C”current has twice the magnitude of a 1 C current.

Alternatively, or additionally, the time duration and other externalconditions of the battery module 262, such as temperature, may becontrolled by the power management module 134 to measure the response ofthe battery module 262. Optionally, one or both of a heating element andcooling element (not shown) may be included in the battery 130 fortemperature control by the power management module 134. A certain ACcurrent (charging or discharging) may also be applied to the battery 130in order to measure the response of the battery module 262.

In accordance with at least one embodiment described herein, theresponse measured by the power management module 134 may comprise aterminal voltage or current of the battery module 262. Alternatively oradditionally, the measurement response may comprise a secondary quantitygenerated based on the terminal voltage or current of the battery module262. For example, the power management module 134 may measure a compleximpedance or charge differential of the battery module 262.

The power management module 134 may request, via the battery processor252, that the measurement circuitry 260 measure the terminal voltage orbattery current of the battery module 262 in order to characterize theelectrical response of the battery module 262 under differentconditions. Alternatively, an electromagnetic response of the batterymodule 262, such as an electromagnetic radiation spectrum, may becharacterized. The response of the battery module 262 may be measuredunder different known conditions in which characteristic responses ofauthentic batteries are observable, and which would generally not all bereproducible in inauthentic batteries within the typical production runof the battery 130. Because authentic batteries are likely to exhibiteach characteristic response to some degree, while inauthentic batteriesare far less likely to exhibit the characteristic responses, the powermanagement module 134 may authenticate the battery 130 by comparing thecharacterized responses of the battery module 262 with correspondingreference responses that have been determined for authentic batteriesand stored in the power management module 134.

In some embodiments, the power management module 134 may performauthentication of the battery 130 based on a single characteristicresponse of the battery module 262. This may be appropriate, forexample, where the actual measured response of the battery module 262 isvery close to reference values over the entire life of the battery 130.In such cases, characterization of a single response of the batterymodule 262 may adequately distinguish between authentic and inauthenticbatteries, and with enough accuracy to provide a basis forauthentication of the battery 130.

In some embodiments, to increase the robustness of the authenticationprocess, the power management module 134 may characterize a number ofdifferent responses of the battery module 262 taken under differentconditions. Further description of some example responses is providedbelow. If at least a threshold number of the characterized responses arematched to corresponding reference responses, then the power managementmodule 134 authenticates the battery 130. As needed, the powermanagement module 134 may characterize additional responses of thebattery module 262 until a positive authentication is made.

However, if fewer than the threshold number of characterized responsesof the battery module 262 match corresponding reference responses storedin the power management module 134, the battery 130 is not authenticatedfor use with the mobile device 100. In such cases of a failedauthentication, the battery 130 may be identified as a third-partyunauthorized or counterfeit battery or, optionally, additional responsesmay be characterized before the battery 130 is determined to beinauthentic. The threshold number of characterized responses required toestablish a positive or failed authentication is variable and may dependon the desired robustness, exactness, or both robustness and exactnessof the authentication process.

In any case of a failed authentication, the main processor 102 may theninitiate further processing or sequences as a precaution to reduce thepossibility of the inauthentic battery causing damage to the mobiledevice 100. As noted above, damage may be caused to the mobile device bycharging of the battery 130 using methods designed for authentic batterypacks and that are incompatible with inauthentic battery packs.

As some non-limiting examples, if the battery 130 is identified as athird-party unauthorized or counterfeit battery, then the main processor102 may execute software that provides user feedback, controls radioaccess, and prevents the mobile device 100 from operating for longerthan a certain time, etc. In some embodiments, the main processor 102will not charge an inauthentic battery pack (e.g., a battery pack thatfails the authentication process) or will only permit charging to amaximum terminal voltage occurring at less than full charge capacity.This way, the likelihood of overcharging the battery 130 is reduced. Inother embodiments, if the battery 130 is identified as a third-partyunauthorized or counterfeit battery, then the main processor 102 may beconfigured to not allow the mobile phone 100 to operate in its normalmode of operation. Instead, the main processor 102 may be configured toprovide an indication that the battery 130 is not authenticated for use.For example, the main processor 102 can cause a suitable graphicalindication to be displayed on the display 110 (FIG. 1).

In some embodiments, the power management module 134 may communicatewith the battery processor 252 ahead of performing authentication toreceive an indication of the model of the battery 130. For example, thepower management module 134 may read the value of the battery IDresistor or request a battery ID value from the battery processor 252 toindicate the battery model. Optionally, the power management module 134may also perform a preliminary cryptographic authentication of thebattery 130 (although as noted above, some inauthentic batteries maypass the cryptographic authentication despite not being, in fact,authentic).

After obtaining the indication of the battery model, the powermanagement module 134 then selects one or more specified responsesstored in the power management module 134 associated with the indicatedbattery model for comparison with the characterized response of thebattery 130. In the case of an inauthentic battery, even if the battery130 successfully provides the correct battery ID or passes thepreliminary cryptographic authentication, the power management module134 may perform authentication of the battery 130 based on the measuredphysical and electrical parameters of the battery module 262.

The battery 130 will be determined by the power management module 134 tobe inauthentic, even if otherwise appearing to be an authentic battery,should the battery 130 be unable to reproduce the reference electricalor electromagnetic responses for authentic batteries of the indicatedmodel under the various different conditions.

Because some variation may occur between even authentic batteriesmanufactured from the same authorized source, the characterized responseof the battery 130 may not exactly match the reference electrical orelectromagnetic response. Accordingly, the power management module 134may define criteria for determining a positive match between thecharacterized response of the battery module 262 and the correspondingreference response. The criteria for a positive match may be defined bythe power management module 134 to provide some flexibility.

As some non-limiting examples, the power management module 134 maydefine a range of values for one or more particular features of thereference response. Corresponding features of the characterized responsemust then be within the defined range before a positive match isdetermined. Alternatively, the power management module 134 may determinea degree of correlation between the characterized and referenceelectrical responses, such as by performing curve fitting, statisticalanalysis and the like, and determine a match between the characterizedand reference responses if there is sufficient correlation.Alternatively, the power management module 134 may process measurementstaken directly from the battery module 262, such as terminal voltage andbattery current, to compute derivative quantities, and to characterizethe response of the battery module 262 based on the derivativequantities.

Various additional factors beyond manufacturing quality also affect theresponse of the battery 130 to different charge conditions. For example,the battery module 262 will behave differently under differenttemperatures and under different charging or discharging currents (e.g.,1 C, 2 C, 0.5 C, etc.). Batteries of different ages or states of healthor that have been cycled a different number of times will also behavedifferently. For example, a battery can be said to age with each cycleof charging and discharging, so that a heavily cycled battery will havea different “age” than a fresh or lightly cycled battery. Aging willalso generally cause the physical and structural integrity (e.g., “stateof health”) of the battery to slowly degrade over time. Accordingly,each of the terms “age” and “state of health”, as the skilled personwill understand, may reflect the condition of the battery module 262relative to an initial condition (referred to herein as a “relativecondition” indicator of the battery). As discussed in more detail below,each of these different conditions may affect one or more differentelectrical or electromagnetic responses of the battery module 262.

Reference electrical or electromagnetic responses for the battery 130may be specified for different electrical excitations of the battery130, such as different charging or discharging currents, but also forthe different external conditions of the battery 130 noted above, suchas age or temperature. The power management module 134 may select whichof the specified electrical or electromagnetic responses to compare withthe characterized electrical or electromagnetic response of the battery130 based on the given conditions of the battery. For example, the powermanagement module 134 may select a particular reference response thathas been specified for a given charging or discharging current and at aparticular temperature. In some embodiments, a temperature sensor (notshown) may be used to detect the temperature of the battery 130 for useby the power management module 134 in selecting a specified electricalor electromagnetic response for comparison.

In some embodiments, if the battery 130 is successfully authenticated asbeing from an authorized source, based on the one or more characterizedelectrical or electromagnetic responses, the power management module 134additionally may estimate a relative condition of the battery 130. Asthe battery 130 ages from its initial condition, its electricalperformance may change over time. Each different characteristic responseof the battery 130 is specified for authentic batteries of differentages or states of health. However, in some embodiments, the relativecondition of the battery 130 may be determined at the same time that thebattery 130 is authenticated as being from an authorized source. Invariant embodiments, the relative condition of the battery 130 may alsobe determined without requiring that that battery 130 be specificallyauthenticated as being from an authorized source.

By way of example, after first authenticating a particular model of thebattery 130, the power management module 134 may then estimate therelative condition of the battery 130 by comparing the characterizedresponse for the battery module 262 to one of the different referenceresponses for authentic batteries of different ages. The specifiedresponse most closely matching the characterized response provides thebasis for estimating the relative condition of the battery 130. Toincrease the accuracy of the estimate or to validate an assessment ofthe relative condition (e.g. age) of the battery, the power managementmodule 134 can perform multiple different comparisons. The relativecondition of the battery 130 can be determined based upon which estimateprovides the closest overall match across all comparisons ofcharacterized and reference electrical responses.

Over time, estimates of the relative condition of the battery may bereassessed. Even if an inauthentic battery managed to mimic an authenticand healthy battery in a first estimation of relative condition, thedegradation pattern of the battery would be highly unlikely to maintainthat match. In a worst-case scenario, an unauthentic battery might gounnoticed for a limited number of cycles. As noted below, maintaining ahistory of determined estimates of the relative condition of the batterymay assist in the determinations of the authenticity, age, and state ofhealth of a battery.

In some embodiments, if the power management module 134 determines thatthe battery 130 is in moderate or relatively poor condition as comparedto a fresh battery, for example due to heavy cycling of the battery 130,the power management module 134 may take a specified action to alert theuser of the mobile device 100 to the degrading condition of the battery130. For example, but without limitation, the power management module134 may instruct the main processor 102 to display a warning on thedisplay 110 (FIG. 1). The display may indicate an estimate of theremaining usable life of the battery 130, which provides the user withsome indication of when to replace the battery 130. In some other cases,for example, where the relative condition of the battery 130 hasdegraded even further, the main processor 102 may even disable furtheruse of the mobile device 100 until the battery 130 is replaced with anew battery.

In one example embodiment, the ability of the power management module124 to determine the relative condition of battery 130, which mayreflect the age and state of health of battery 130, allows for aprediction of when battery 130 is predicted to fail. This applicationmay also be referred to as “warranty prediction”. When the relativecondition of battery 130 is determined, and it is predicted that thebattery 130 will fail within a certain period of time or that failure isimminent, a corresponding data message, signal or other indicator may beautomatically transmitted by the mobile device 100 to, for example, themanufacturer of the mobile device 100 or battery 130. If many batteriesare predicted to fail within the same period of time, this may providethe manufacturer with advance notice of this condition, allowing themanufacturer to plan accordingly (e.g. prepare to deal with a recall ormass return of battery stock, plan for an increase in the sale of newbatteries, etc.).

In another example embodiment, the ability of the power managementmodule 124 to determine the relative condition of battery 130 may alsoallow batteries purported to be of a certain age or condition to beverified. For example, if an authentic battery is being sold as a “new”battery when in fact the battery has been heavily cycled despiteappearing cosmetically to be a new battery, the power management module124 may be configured to act as an “age meter” for example, to determinethe age of the battery, or to verify that the age or condition (or both)of the battery is consistent with the age or condition (or both) that itis purported to be in.

Some different electrical or electromagnetic responses of the batterymodule 262 that may be used as a basis for authenticating the battery130, or for estimating the relative condition of the battery 130, orboth, will now be described. Each of the described electrical orelectromagnetic responses may be used by the power management module 134independently or in combination with any number of the other describedelectrical or electromagnetic responses to authenticate or estimate therelative condition of the battery 130. Accordingly, a positive match maybe required for any one, some combination of more than one, or in somecases all of the described electrical or electromagnetic responses,before the battery 130 will be authenticated. In the event that one ormore of the electrical or electromagnetic responses not match, the mainprocessor 102 may initiate one of the above-described procedures forhandling a failed authentication of the battery 130.

For convenience, the different electrical or electromagnetic responsesdescribed herein are organized under section headings. However, itshould be appreciated that the following list is illustrative only andnot exhaustive of the possible different electrical or electromagneticresponses of the battery module 262 that may be used in the describedembodiments to enhance battery security and authentication. Use ofsection headings shall not have the effect of limiting the scope of thedescribed embodiments in any way.

Battery Capacity

Referring now to FIGS. 5A and 5B, the relationship between cell voltageand battery capacity over time for authentic and inauthentic batteriesis illustrated. Graph 300 in FIG. 5A plots cell voltage on the y-axis(in volts, V) against capacity removed on the x-axis (in ampere-hours,A.h) at various representative points throughout the life of anauthentic battery. In graph 300, cell voltage represents the terminalvoltage measured at output terminals of battery module 262, whilecapacity removed represents the charge removed (or alternatively stored)in the battery module 262 over a single charge cycle normalized by thecapacity of the battery 130. As will be appreciated, 1 A.h is equivalentto the amount of electric charge (in Joules, J) that 1 A of currenttransfers in 1 h of time and, therefore, graph 300 could be re-writtenwith units of Joules on the x-axis.

For an authentic battery manufactured by an authorized source, the cellvoltage and charge removed (or stored) in the battery module 262 will becharacteristically related to one another as shown in FIG. 5A. Curve 305represents the characteristic relationship between cell voltage andcharge capacity when the battery 130 (FIG. 4) is new. Curves 310, 315and 320 represent the relationship between these two battery parametersas the battery 130 ages, for example, in four-month intervals. Thus,curve 310 may represent the relationship between cell voltage versuscharge removed when the battery 130 is 4 months old, curve 315 mayrepresent the relationship when the battery 130 is 8 months old, andcurve 320 may represent the relationship when the battery 130 is 12months old, although these battery ages are examples only.

As indicated by FIG. 5A, the age of the battery 130 generally affectsthe relationship between cell voltage and charge capacity of the batterymodule 262. For example, the charge capacity of the battery 130generally decreases over the lifetime of the battery 130, so that inolder or more degraded batteries, progressively less charge tends to bestored or removed per unit voltage change from full charge (atapproximately 4.1V). In other words, the battery 130 over time graduallyloses the ability to store charge due to aging or wearing out. Thisdegradation of the relative condition of the battery 130 is indicated bythe trendline 325 on graph 300.

During operation of the mobile device 100, power management module 134(FIG. 4) monitors the terminal voltage of the battery module 262 (FIG.4), as well as the battery current discharged from the battery module262 as a function over time to compute capacity removed. From these twomeasured battery parameters, power management module 134 is able tocharacterize the voltage-capacity response of the battery 130.Alternatively, the power management module 134 may monitor the terminalvoltage and charging current of the battery module 262 during chargingin order to characterize the voltage-capacity response of the battery130.

In addition to age or state of health, the voltage-capacity response ofthe battery 130 will generally depend on other conditions of the battery130. Curves 305, 310, 315 and 320 therefore represent thevoltage-capacity response of the battery 130 only under a given set ofconditions and would not generally be identical for different conditionsof the battery 130. Different conditions for the battery 130 wouldtypically generate different cell voltage-charge capacity responses.

As some non-limiting examples, curves 305, 310, 315 and 320 may begenerated for a particular operating temperature of the battery module262 and for a particular rate of charge or discharge. Although notspecifically illustrated on graph 300, additional voltage-capacityresponses of the battery 130 for multiple different temperatures,different charge or discharge rates, or both different temperatures anddifferent charge or discharge rates are specified and stored in thepower management module 134.

Referring now to graph 350 of FIG. 5B, the power management module 134may also use the voltage-capacity response characterized for the battery130 as a basis for authenticating that the battery 130 was produced byan authorized source. Curves 355, 360, 365 and 370 correspond to thevoltage-capacity responses of an inauthentic battery that are measuredunder the same conditions as curves 355, 360, 365 and 370, shown in FIG.5A, which were measured for an authentic battery. Trendline 375 on graph350 shows that the relative condition of inauthentic batteries can bepredicted to degrade over time as well. Region 380 on graph 350indicates the general location of the trendline 325 in FIG. 5A.

As seen from FIG. 5B, the features of curves 355, 360, 365 and 370 forthe inauthentic battery do not exactly match the features of curves 305,310, 315 and 320 shown in FIG. 5A for the authentic battery. Forexample, trendline 375 on graph 350 is drawn through the respectiveknee-points of curves 355, 360, 365 and 370, which roughly correspond tothe full charge capacity of the battery 130 for a given age. Region 380drawn on graph 350, which indicates the location of the correspondingknee-points of curves 305, 310, 315 and 320 for the authentic battery,does not align with trendline 375.

Accordingly, in some embodiments, the power management module 134 mayestimate the charge capacity of the battery 130 by detecting theknee-point of the voltage-capacity response, and compare the estimatedcharge capacity against reference values. Using the results of thecomparison, alone or in combination with other comparisons, the powermanagement module 130 may authenticate or estimate the relativecondition of the battery 130, or both. Authentic batteries will losetheir charge capacity at different rates in comparison to inauthenticbatteries, which will be detectable by the power management module 134in at least some cases.

Charge Differential

Referring now to FIGS. 6A and 6B, the relationship between chargedifferential and battery voltage for authentic and inauthentic batteriesis illustrated. Graph 400 in FIG. 6A plots charge differential on they-axis (in units of ampere-hours per volt, (A.h)/V) against batteryvoltage on the x-axis (in units of volts, V) for a new battery. In graph400, the plotted charge differential represents a rate of change of acharge capacity of the battery module 262 during charging with respectto a terminal voltage of the battery module 262. The charge differentialis plotted as a function of the terminal voltage of the battery module262.

Each point on a curve plotted on graph 400 represents, for a differentterminal voltage of the battery module 262, the incremental chargedelivered to the battery module 262 that results in a correspondingincremental increase in the terminal voltage of the battery module 262.Curves 405 and 410 represent the responses of two different authenticbatteries manufactured from two different authorized sources. Curve 415represents the response of an inauthentic battery. Each of curves 405,410 and 415 are generated from measurements taken during charging of anew battery and under equivalent external conditions (e.g.,temperature).

As can be seen from FIG. 6A, depending on the particular controlsimposed on the manufacturing process, two different authentic batteriesfrom two different authorized sources may exhibit a similar chargedifferential response during charging. However, in at least some cases,inauthentic batteries would not generally exhibit a response identicalwith the response of authentic batteries.

For example, curves 405 and 410 have generally similar trajectories andeach show characteristic features at approximately the same locations.Region 420 indicated on graph 400 shows that curves 405 and 410 eachexperience a local maximum of between 2 and 3 (A.h)/V for a batterymodule 262 terminal voltage at between approximately 3.8 V andapproximately 3.9 V. Region 425 shows that curves 405 and 410 each alsoexperience another local maximum of approximately 7 (A.h)/V for abattery module 262 terminal voltage at between approximately 3.9 V andapproximately 4.0 V. While illustrated numerically for ease ofreference, it should be appreciated that curves 405 and 410 are notrestricted only to the values or ranges specifically indicated.

For the same conditions, curve 415 corresponding to the inauthenticbattery does not exhibit the same general features as curves 405 and 410corresponding to the authentic batteries. As one example, while curve415 experiences a local maximum between approximately 3.9 V andapproximately 4.0 V, the value of the local maximum is only about 3(A.h)/V and does not coincide with region 425. As another example, curve415 does not exhibit any appreciable local maximum between approximately3.8 V and approximately 3.9 V corresponding to the region 420. As athird example, curve 415 also shows a second local maximum betweenapproximately 4.0 V and approximately 4.1 V, where no correspondinglocal maximum is observed in curves 405 and 410.

In some embodiments, during charging of the battery module 262, thepower management module 134 (FIG. 4) measures the terminal voltage andcharging current supplied to the battery module 262 as a function oftime to characterize the charge differential response of the battery 130(FIG. 1), i.e., to generate a curve 405, 410 or 415. The powermanagement module 134 then compares one or more features of thecharacterized charge differential response against reference chargedifferential responses that have been specified for authentic batteriesand stored in the power management module 134. Based on the results ofthe comparison (optionally with other comparisons), the power managementmodule 134 may authenticate or estimate the relative condition of thebattery 130.

Referring now to FIG. 6B, graph 450 illustrates the charge differentialresponse for the same batteries as in graph 400 of FIG. 6A, but aftereach of the batteries has been aged, such as through heavy cycling.Graph 450 has the same units and is plotted on the same scale as graph400 shown in FIG. 6B. Curves 455 and 460 represent the responses of thetwo authentic batteries, and curve 465 represents the response of theinauthentic battery. Each of curves 455, 460 and 465 is generated againfrom measurements taken during charging under equivalent externalconditions (e.g., temperature).

As will be appreciated from FIG. 6B, even after aging, the chargedifferential responses of the two authentic batteries manufactured fromdifferent authorized sources remain similar and distinguishable from thecharge differential response of the inauthentic battery. For example,curves 455 and 460 again each experience a local maximum, which isindicated by region 470, for a battery terminal voltage of betweenapproximately 3.8 V and approximately 3.9 V. Curves 455 and 460 alsoeach experience a second local maximum at between approximately 3.9 Vand approximately 4.0 V, which is indicated by region 475. Curve 465corresponding to the inauthentic battery only exhibits a single localmaximum at between approximately 4.0 V and approximately 4.1V.

The charge differential response of the battery 130 also provides abasis for estimating the relative condition of the battery 130. Forexample, while curves 455 and 460 each exhibit a local maximum in region475, the height of the local maximum is smaller as compared to the localmaximum seen in region 425 of FIG. 6A. By detecting the height of thelocal maximum that occurs between approximately 3.9 V and approximately4.0 V for the battery 130 and comparing against specified chargedifferential responses for authentic batteries, the power managementmodule 134 in some embodiments can estimate the relative condition ofthe battery 130 based on the charge differential response of the batterymodule 262.

The characteristic charge differentials exhibited by authentic andinauthentic batteries are explainable in part by the underlyingelectrochemistry of the battery 130. For example, rechargeable batteriesmay be manufactured using different materials for each of the anode,cathode and electrolyte. Nickel-cadmium (NiCd) batteries typically use anickel (III) oxide-hydroxide cathode, a cadmium electrode, and analkaline electrolyte, such as potassium hydroxide. Compared to NiCdbatteries, nickel-metal hydride (NiMH) batteries typically use adifferent metallic compound for the anode, which can be a rare earthmixture.

More recently, rechargeable lithium ion batteries (LIB) have beendeveloped, in which the migration of ions of lithium from the batteryanode to the battery cathode during discharge provides the electromotiveforce of the battery. During charging, an external electrical powersource (e.g., the charging circuit) applies a charging voltage to thebattery of the same polarity as the battery terminals, but of a largermagnitude, which causes a process of reverse migration to occur. Theions of lithium collected at the cathode are forced back to the anode,wherein they become embedded in a process known as intercalation.

Because the intercalation of the lithium ions occurs more readily atcertain discrete energy levels, the charge input rate of the battery 130(i.e., the charge differential) varies throughout the charge cycle ofthe battery 130 in a manner that is characteristic to the internalelectrochemistry of the battery 130. As suggested by FIGS. 6A and 6B,inauthentic batteries will not typically match the intercalation ratesof authentic batteries. Even if the inauthentic battery is designedusing the same or a similar internal electrochemical process, ionintercalation is affected by other factors such as the battery size andgeometry.

While explained primarily with reference to the electrochemistry oflithium ion batteries, NiCd and NiMH batteries also utilize ionintercalation during charging to embed charge carriers in the batteryanode. As a result, NiCd and NiMH batteries also tend to exhibit chargedifferential responses during charging that are characteristic of theunderlying electrochemistry and battery topology. In each case, theparticular charge differential response of the battery 130 may provide abasis for authenticating or estimating the relative condition of thebattery 130, or both.

Referring now to FIGS. 7 and 8, the charge differential response of thebattery 130 (FIG. 4) may be characterized by the power management module134 in an alternative form to what is illustrated in FIGS. 6A and 6B.

Graph 500 in FIG. 7 plots voltage on the y-axis (in units of volts, V)against charge time on the x-axis (in units of minutes, min). The y-axisvalues in graph 500 represent measured terminal voltages of the batterymodule 262 (FIG. 4) at the point during charging of the battery 130where the charge differential (as defined above with respect to FIGS. 6Aand 6B) reaches its maximum value. The x-axis values in graph 500represent the time during the charge cycle at which the maximum chargedifferential occurred. Accordingly, graph 500 is specific to aparticular charging current (e.g., 1 C) and could be equivalently drawnwith units of Joules on the x-axis.

Region 505 on graph 500 is defined to include all points having ay-coordinate less than 4.0 V and an x-coordinate less than 250 min.Region 510 includes all points not included in region 505. In someembodiments, the power management module 134 may determine if thebattery 130 is authentic according to whichever region, 505 or 510, themeasured battery voltage at peak charge differential is located in. Itshould be appreciated that the specific boundaries illustrated in FIG. 7are illustrative only and may have different values depending on theconditions under which the parameters of the battery 130 are measured.

Data points 515 are each located within region 505 and correspond tomeasurements taken on authentic batteries. For example, data points 515can represent measurements taken on the same authentic battery or,alternatively, from different authentic batteries manufactured fromdifferent authorized sources. Data points 520 are each located withinregion 510 and correspond to measurements taken on inauthenticbatteries. Again, for example, data points 520 can representmeasurements taken on the same inauthentic battery or, alternatively,from different inauthentic batteries.

As will be appreciated from FIG. 7, data points 520 have generallydifferent x-coordinates and y-coordinates relative to data points 515.This indicates that the peak charge differential for the inauthenticbatteries occurred both at a different terminal voltage of the batterymodule 262 (˜4.03 V as opposed to ˜3.95 V) and at a different timeduring the charge cycle (˜262.5 min as opposed to ˜200 min). Each orboth of these differences may be detected and used by the powermanagement module 134 to authenticate the battery 130.

Referring now to FIG. 8 specifically, the charge differential responseof authentic and inauthentic batteries is also characterizable ormeasurable over the lifetime of the battery 130 (FIG. 4). Graph 550 inFIG. 8 plots voltage on the y-axis (in units of volts, V) against chargecapacity on the x-axis (in units of ampere-hours, A.h). For each datapoint plotted on graph 550, the y-axis value represents measuredterminal voltages of the battery module 262 at the point during chargingof the battery 130 where the charge differential (as defined above withrespect to FIGS. 6A and 6B) reaches its maximum value. The correspondingx-axis value then represents the charge capacity of the battery 130 atwhich the maximum charge differential occurred and, accordingly,corresponds to a particular tap time during charging or discharging.Charge capacity may be estimated, for example, by integrating thecharging current supplied to the battery 130 over time during the chargecycle.

Data points 555 correspond to measurements taken on an authentic batteryat various intervals over the lifetime of an authentic battery. Theauthentic battery trendline 560 indicates the general trajectory of thedata points 555 as the authentic battery ages, from right (new/freshbattery) to left (aged/cycled battery). As the authentic batterytrendline 560 indicates, over the lifetime of the battery, peak chargedifferentials tend to occur at increasing terminal voltages andcorrespondingly decreasing charge capacities of the battery module 262.

Graph 550 also includes data points 565, which correspond tomeasurements taken on an inauthentic battery over the lifetime of theinauthentic battery, and under similar conditions as the data points 555generated for the authentic battery. The general trajectory of datapoints 565 is indicated by inauthentic battery trendline 570, whichshows that for the inauthentic battery, as well as the authenticbattery, peak charge differential tends over the lifetime of the batterytends to drift toward increasing terminal voltages and correspondinglydecreasing charge capacities of the battery module 262.

As FIG. 8 shows, the power management module 134 may authenticate thebattery 130 as being from an authorized source using the measurement ofpeak charge differential. For example, power management module 134 (FIG.4) may distinguish between data points on the two trendlines 560 and 570to define reference peak charge differential values for authenticbatteries. Measurements of peak charge differential for the battery 130may then be compared against each of the authentic battery trendline 560and the inauthentic battery trendline 570. If the power managementmodule 130 determines that the peak charge differential measurementbetter matches the authentic battery trendline 560, the battery 130 maybe authenticated. Otherwise, if the peak charge differential measurementbetter matches the inauthentic battery trendline 570, the powermanagement module 134 may refuse to authenticate the battery 130 and,optionally, perform additional comparisons based on other electricalresponses of the battery 130 to make a conclusive authentication.

In addition to performing authentication, power management module 134may also estimate the relative condition of the battery 130 using themeasurement of peak charge differential. The relative condition of thebattery 130 may also be estimated without performing authentication, invariant embodiments. For example, power management module 134 maydetermine where on the authentic battery trendline 560 the measurementof peak charge different is located in order to estimate the relativecondition of the battery 130. As the battery 130 ages, the measurementof peak charge differential will tend to move along the authenticbattery trendline 560, from right to left, at a characteristic rate thatprovides one possible basis for estimating the relative condition of thebattery 130.

While FIGS. 7 and 8 present some numerical examples, it should beappreciated that the particular data points plotted on graphs 500 and550 are illustrative only and may depend on the particular conditions ofthe battery 130 when the measurements are taken. For example,temperature and charging/discharging rate will generally affect themeasurement of peak charge differential. Accordingly, in someembodiments, different reference peak charge differentials may bedetermined for different external conditions of the battery 130, such astemperatures and charging/discharging rates, and stored in the powermanagement module 134 for use in authenticating or estimating therelative condition of the battery 130, or both.

Voltage Slump

Referring now to FIGS. 9A and 9B, a transient response of the battery130 (FIG. 4) to alternating current may exhibit characteristic featuresthat provide a basis for the power management module 134 (FIG. 4) todifferentiate between authentic and inauthentic batteries. Graph 600 inFIG. 9A plots battery terminal voltage on the y-axis (in units of volts,V) against time on the x-axis (in units of minutes, min) for a new/freshbattery. Graph 650 in FIG. 9B plots battery terminal voltage on they-axis (in units of volts, V) against time on the x-axis (in units ofminutes, min) for an aged/cycled battery.

Curve 605 plotted on graph 600 represents the transient response of anew, authentic battery to a large intermittent (e.g., pulsed) currentdraw. For example, curve 605 may represent the current drawn from thebattery 130 during transmission or receipt of wireless communications bythe communication subsystem 104 (FIG. 1). Alternatively, curve 605 mayrepresent an artificial current draw from the battery 130 requested bythe power management module 134 after interrupting normal operation ofthe mobile device 100.

Each cycle in battery voltage curve 605 consists of a high voltage level610 and a low voltage level 615. The high voltage level 610 results whenno or little current is being drawn from the battery 130 and correspondsapproximately to the open circuit voltage of the battery module 262.However, when a large current is drawn from the battery 130, theterminal voltage of the battery module 262 characteristically “droops”or “slumps” down to the low voltage level 615. When the large currentdraw on the battery 130 ceases, the battery voltage rebounds to the highvoltage level 610.

As seen in FIG. 9A, each battery “droop” or “slump” may be considered toundergo a number of transitions that define at least three discretephases. In phase 620, the battery voltage curve 605 undergoes arelatively steep decrease from the high voltage level 610 to anintermediate voltage level somewhat above the low voltage level 615. Inthe next phase 625, the battery voltage curve 605 undergoes a second,more gradual decrease from the intermediate level down to the lowvoltage level 615. In the final phase 630, the battery voltage curve 605holds steady at the low voltage level 615 until the large current drawon the battery 130 is stopped and the battery voltage curve 605 thenrebounds to the high voltage level 610. Similar discrete phases may beobserved as the battery voltage curve 605 rebounds to the high voltagelevel 610.

The phases 620, 625 and 630 of the battery voltage curve 605 areexplainable with reference to the internal electrochemistry of thebattery 130. The relatively rapid decrease of the battery voltage curve605 in phase 620 corresponds to the interval voltage drop in the batterymodule 262 due to the effective series resistance (ESR) of the batterymodule 262. The voltage difference between the high voltage level 610and the intermediate voltage level, in relation to the battery current,therefore provides an estimate of the battery ESR. The second, moregradual voltage drop in phase 625 of the battery voltage curve 605 isdue at least in part to one or more polarization layers building upinside the battery module 262 at one or more electrode/separatorinterfaces (explained below with reference to FIG. 10) when the battery130 is being discharged.

Different internal battery electrochemistries give rise to differentbattery droop characteristics, not just between batteries manufacturedfrom different sources or having different geometries, but also over thelifetime of the battery 130. Accordingly, the amounts of the two voltagedrops caused respectively by the battery ESR and a polarization layerprovide the power management module 134 with bases for comparisonbetween authentic and inauthentic batteries. For example, the powermanagement module 134 may measure one or both of these voltage drops andcompare against reference voltage drops for authentic batteries.Matching of measured to reference values may allow the power managementmodule 134 to authenticate the battery 130.

Additionally, the characteristic voltage drops caused respectively bythe battery ESR and the polarization layer provide the power managementmodule 134 with at least two bases for estimating the relative conditionof the battery 130.

Referring now to FIG. 9B, battery voltage curve 655 represents thetransient response of the same battery characterized by battery voltagecurve 605 in FIG. 9A, but no longer new. For example, curve 655 mayrepresent an aged or heavily cycled battery. While battery voltage curve655 has the same general waveform as battery voltage curve 605,comprising alternating high and low voltage levels 660 and 665, thedroop characteristics of battery voltage curve 665 have changedsomewhat. In particular, the voltage drops experienced in phases 670 and675 of battery voltage curve 655 are each respectively larger thancorresponding voltage drops associated with phases 630 and 625 ofbattery voltage curve 605 determined for the new battery (shown in FIG.9A).

To some extent, these differences can be explained by the decreasedmobility of the charge carriers (e.g., the ions of lithium) inside thebattery module 262 as the battery 130 ages. Decreased ion mobility tendsto increase the ESR of the battery 130 and, due to the increasedsusceptibility of the battery electrolyte, cause a thicker polarizationlayer to form on the battery anode. Many aged or heavily cycledbatteries will therefore exhibit larger ESR and thicker polarizationlayers over time.

In some embodiments, the power management module 134 measures one orboth of the voltage drops due to ESR and polarization in order tocharacterize the transient response of the battery 130. By comparing themeasured voltage drops with changing reference values over time, thepower management module 134 is able to estimate the relative conditionof the battery 130. While FIG. 9B shows the transient response of aheavily cycled battery, in relation to the transient response of a newbattery shown in FIG. 9A, it should be appreciated that inauthenticbatteries may also exhibit different droop characteristics as comparedto authentic batteries. Thus, in some embodiments, power managementmodule 134 also uses the characterized transient response of the battery130 to perform authentication.

Electrochemical Impedance Spectroscopy (EIS)

Referring now to FIGS. 10, 11 and 12A-12D, battery impedance modelingand estimation performed under conditions of alternating current (AC),hereinafter referred to as “electrochemical impedance spectroscopy”(EIS), provides a further basis for differentiating between authenticand inauthentic batteries. Accordingly, in some embodiments, the powermanagement module 134 performs (FIG. 4) EIS on the battery 130 toperform authentication.

In EIS, a network model is proposed to represent the AC impedance ofdifferent internal components or structures of a known authenticbattery. Each internal battery component included in the network modelis represented by a corresponding battery parameter. Specificrelationships (e.g., series or parallel connections) are also definedbetween certain of the battery parameters included in the network modelto reflect different physical relationships between the internal batterycomponents represented in the network model. Values for the differentbattery parameters are then solved by measuring the total compleximpedance of the authentic battery under different AC frequencyexcitations, and performing systems analysis on the network model todetermine values for each individual battery parameter. After computingvalues for the different battery parameters, the complete network modelof the authentic battery provides a measure of the reference impedanceof authentic batteries for comparison against measured impedances of thebattery 130.

As will be appreciated, impedance may be related to voltage throughcurrent. Accordingly, in some embodiments, as an alternative tocomparing measured and reference impedances, the power management module134 may be configured to measure terminal AC voltages of the batterymodule 262 for a given AC current, and compare the measured terminal ACvoltages against reference terminal AC voltages derived from thereference impedance of the authentic battery and the given AC current.

Referring now to FIG. 10 specifically, there is shown a simplified modelof a battery winding 700 that may be included in the battery module 262(FIG. 4) in some embodiments. The battery winding 700 is shownschematically in cross-sectional view for simplicity and clarity ofillustration, although it should be appreciated that in the describedembodiments, the battery winding 700 may be rolled or stacked within thebattery module 262 to provide increased density. The battery module 262may also include more than one battery winding 700 in differentembodiments.

Battery winding 700 includes a cathode 702 separated from an anode 704by a separator 706 inside of a housing 708. As noted above, the cathode702 and anode 704 may be made from different materials depending on theelectrochemistry of the battery 130. Current collector 710 backs thecathode 702 and provides an electrical path to tab 712, which leads tothe exterior of the housing 708 and is thereby used as an externalconnection for the battery winding 700. Similarly, current collector 714backs the anode 704 and provides an electrical path to tab 716, whichleads to the exterior of the housing 708 and is thereby used as anotherexternal connection for the battery winding 700. The tabs 712 and 716may also together form the external battery terminals for the batterymodule 262.

An electrolyte is provided in the interior space 718 within the housing708, between the cathode 702 and the anode 704. The electrolyte, whichmay be in a liquid or solid phase, contains the charge carriers thatprovide the battery winding 700 with an electromotive force (EMF) whencharged. For example, in lithium-ion batteries, the electrolyte is aliquid containing salts of lithium that oxidize to produce lithium ions.The separator 706 divides the interior space 718 into two parts, but ispermeable to the charge carriers, e.g. Li⁺ ions. As the arrows in FIG.10 indicate, the Li⁺ ions pass through the separator 706 from anode 704to cathode 702 during discharge and from cathode 702 to anode 704 duringcharging of the battery 130.

A polarization layer 720 forms on each of the cathode 702 and anode 704due to charge separation and the internal EMF of the battery winding700. The thickness of the polarization layers 720 may depend on thegeometry and relative condition of the battery 130, as well as on thetemperature and discharge rate of the battery 130.

For lithium-ion batteries, a solid electrolyte interphase (SEI) layer722 also forms on the interior surface of the anode 704 between theanode 704 and the associated polarization layer 720. During charging ofthe battery winding 700, some of the electrolyte decomposes on the anode704 and forms the SEI layer 722. While acting as a partial electricalinsulator, the SEI layer 722 still provides overall ionic conductivitybetween the electrolyte and the anode 704. The thickness of the SEIlayer 722 also depends on the geometry and relative condition of thebattery 130. As will be explained, the SEI layer 722 and the othercomponents of the battery winding 130 collaborate to provide the batterywinding 130 with a characteristic AC impedance response.

Referring now to FIG. 11 specifically, there is shown a network model750 used to model the impedance characteristic of the battery winding700 shown in FIG. 10. The network model 750 includes a seriescombination of an inductor (L) 752, a resistor (R_(s)) 754, and two RCelements 756 and 758. The first RC element 756 includes a parallelcombination of a resistor (R_(f)) 760 and a capacitor (C_(pe)) 762. Thesecond RC element 758 includes a parallel combination of a resistor(R_(ct)) 764 and a capacitor (C_(d)) 766.

Each of the battery parameters included in the network model 750represents the electrical characteristic of one or more physicalcomponents of the battery winding 700 shown in FIG. 10. It should beappreciated that the complexity of the network model 750 may be variedby taking into account the electrical characteristics of a greater or afewer number of physical components of the battery winding 700. Thenetwork model 750 is also shown as a linear system in this exampleembodiment, but could also be modified to include some non-linearcomponents to provide a closer approximation of the electricalcharacteristics of the battery winding physical components.

As shown in FIG. 11, inductor 752 models the net inductance of thebattery winding 700 and external wire and other electronic connections.The inductance of these components may be small or negligible and,consequently, in some embodiments the inductor 752 may be omitted fromthe network model 750. Resistor (R_(s)) 754 models the combined seriesresistance of the cathode 702, separator 706, anode 704 and electrolytein the direction of ionic flow within the battery winding 700. The RCnetworks 756 and 758 account for other charge dependent effects in thebattery winding 700.

The RC network 756 accounts for the electrical characteristic of the SEIlayer 722. More specifically, resistor (R_(f)) 760 and capacitor(C_(pe)) 762 model the resistance and capacitance, respectively, of theSEI layer 722. In a similar fashion, the RC network 758 corresponds toand accounts for electrical characteristics of the double polarizationlayer 720. Capacitor (C_(d)) 766 represents the combined capacitanceacross the two polarization layers 720, i.e. between the electrolyte andeach of the cathode 702 and anode 704. Resistor (R_(ct)) 764 models theresistance associated with the transfer of charge carriers between theelectrolyte and one of the cathode 702 and anode 704, through acorresponding one of the polarization layers 720.

The power management module 134, for example, solves values for each ofthe battery parameters included in the network model 750, e.g. usingsystem analysis, to generate the reference impedance response forauthentic batteries over a broad range of frequencies. The referenceimpedance response is stored in the power management module 134 forcomparison against a characterized impedance response of the batterywinding 700, which the power management module 134 may determine bymeasuring the impedance of the battery winding 700 at different ACexcitation frequencies.

Referring now to FIGS. 12A and 12B specifically, the characterized andreference impedances of a new, authentic battery are illustrated. Graph700 in FIG. 12A plots the real and imaginary parts of the batterywinding impedance for different excitation frequencies. Curve 705represents the reference impedance for authentic batteries and curve 710represents the characterized impedance of the battery 130. Theexcitation frequencies increase from region 715 (<approximately 1 Hz)toward region 720 (>approximately 10 kHz).

Graph 750 in FIG. 12B plots the same data as FIG. 12A, but with themagnitude and phase of the battery winding impedance explicitly as afunction of excitation frequency. Accordingly, curve 755 represents thereference impedance magnitude for authentic batteries and curve 760represents the characterized impedance magnitude of the battery 130,each explicitly as functions of excitation frequency. Likewise, curve765 represents the reference impedance phase for authentic batteries andcurve 770 represents the characterized impedance phase of the battery130 as functions of excitation frequency.

As FIGS. 12A and 12B confirm, the solved network model 750 may be usedto predict the impedance of the battery 130 under AC excitation over abroad range of frequencies. Thus, by measuring the impedance of thebattery 130 over a sufficient number of different excitation frequenciesand comparing against reference values, in some embodiments, the powermanagement module 134 may authenticate the battery 130 in terms of itscharacteristic impedance response.

Additionally, the characteristic AC impedance of the battery winding 700provides the power management module 134 with a basis for estimating therelative condition of the battery 130.

Referring now to FIGS. 12C and 12D, the reference and characterizedimpedance responses for a heavily cycled battery are shown.

Graphs 800 and 850 in FIGS. 12C and 12D plot characterized and referenceimpedance data under the same conditions as that of the authenticbattery plotted in FIGS. 12A and 12B, but after the battery has beenheavily cycled.

In graph 800, curve 805 represents the reference impedance for heavilycycled, authentic batteries, while curve 810 represents thecharacterized impedance of the battery 130 after heavy cycling. Theexcitation frequencies again increase from region 815 (<approximately 1Hz) toward region 820 (>approximately 10 kHz). Likewise in graph 850,the same data is presented explicitly in terms of the magnitude andphase of the battery winding impedance as a function of excitationfrequency. In particular, curve 855 represents the reference impedancemagnitude for heavily cycled authentic batteries and curve 860represents the characterized impedance magnitude of the battery 130after heavy cycling frequency. Also, curve 865 represents the referenceimpedance phase for heavily cycled authentic batteries and curve 870represents the characterized impedance phase of the battery 130 afterheavy cycling.

As seen from FIGS. 12C and 12D, the impedance of the battery winding 700changes as the battery 130 ages. Accordingly, to estimate the relativecondition of the battery 130, the impedance response of authenticbatteries at different ages or states of health may be specified andstored in the power management module 134. To estimate the relativecondition of the battery 130, the characterized impedance response ofthe battery 130 is then compared against and matched to one of thespecified reference responses for authentic batteries. The location ofthe characterized impedance on the curve of reference impedances may becorrelated by the power management module 134 with a certain age orstate of health.

While not explicitly shown, if the characterized impedance response ofthe battery 130 does not correspond to one of the specified impedanceresponses for authentic batteries, the battery 130 will not beauthenticated. Alternatively, the power management module 134 willcompare a different characterized response of the battery 130 toreference values before determining that the battery 130 is or is notauthentic.

Electromagnetic Radiation (EMR)

Referring now to FIGS. 13A and 13B, the spectrum of electromagneticradiation (EMR) emitted from the battery 130 (FIG. 4) during operationprovides the power management module 134 (FIG. 4) with still anotherbasis for comparison between authentic and inauthentic batteries. Insome embodiments, the battery 130 is formed by folding or rolling one ormore of the battery windings 700 shown in FIG. 10 into a more compactthree-dimensional shape, typically a rectangular prism or cuboid. Thefolded or rolled trajectory of the battery windings 100 turns thebattery 130 into a pseudo antenna, so that battery current flowingthrough the battery windings 700 causes radiation of electromagneticenergy that is generally detectable by nearby receiving antennas 170 onthe mobile device 100.

The physical geometry of the battery 130 will generally affect thespectrum of EMR emitted from the battery 130. For example, the length ofthe battery windings 700 will affect the resonant frequency of thepseudo antenna provided by the battery 130. As will be appreciated, thesignal power of an antenna will be maximized when the antenna is drivenat the resonant frequency, but will decrease toward zero as the signaldrive frequency is shifted away from the antenna resonant frequency.Depending on the resonant frequency of the battery windings 700, thebattery 130 will emit EMR over a range of frequencies centered on theresonant frequency.

In some embodiments, a capacitor 180 is connectable to the battery 130by a controlled switch 185, for example, so that the resonant frequencyof the battery 130 can be shifted between a natural resonant frequencyand an adjusted resonant frequency. The power management module 134, oralternatively the main processor 102 (FIG. 1), may control the switch185 to selectively connect or disconnect the capacitor 180 to thebattery winding 700.

As another example, most practical antennas have a certain radiationpattern comprising one or more “lobes” in which signal strength iscomparatively larger than at other angles. Thus, the signal emitted inone direction will not necessarily have equal strength to the signalemitted in a different direction. The direction of folding or rolling ofthe battery windings 700 can, in some cases, also affect the directivityof the EMR emitted from the battery 130.

As illustrated by FIGS. 13A and 13B, in some embodiments, the mobiledevice 100 includes a plurality of receiving antennas 170 of variousshapes and sizes and at generally different physical locations on themobile device 100. For example, some of the antennas 170 may be includedin the communication subsystem 104 illustrated in FIG. 2 and used forcommunicating with a long-range wireless network. Other of the antennas170 may be part of the short-range communications subsystem 122 (FIG. 1)and used for communicating with other mobile devices over a short-rangewireless network. The antennas 170 may be designed or tuned to detectsignals in different frequency ranges depending on the particularpurpose of the given antenna 170. For illustrative purposes, theantennas 170 are shown in FIGS. 13A and 13B as loops of generallydifferent sizes to reflect this possibility.

Depending on the resonant frequencies of the battery winding 700 and theantennas 170, EMR emitted from the battery 130 at certain frequencieswill be detectable in the antennas 170 with corresponding referencesignal strengths relative to the signal power of the emitted EMR. Thedirectivity and spatial orientation of the battery winding 700 inrelation to the each respective antenna 170 will also generally affectthe received signal strength of the EMR detected at each antenna 170.The capacitor 180 may be connected to the battery winding 700 in orderto shift the resonant frequency of the battery winding 700 to a levelthat better matches the antennas 170 and causes the EMR emitted from thebattery winding 700 to be detectable by a greater number of the antennas170.

Because inauthentic batteries will have a generally different internalelectrochemistry and physical structure as compared to authenticbatteries manufactured from authorized sources, the spectrum of EMRemitted from authentic batteries will generally differ from that ofinauthentic batteries. The EMR emitted from an inauthentic battery willtherefore not be detected by the same antennas 170 with the sameapproximate received signal strength, as compared to authenticbatteries.

In some embodiments, the power management module 134 measures the EMRspectrum of the battery 130 based upon the signal strength of the EMRreceived at each of the antenna 170. For this purpose, the powermanagement module 134 may drive the battery winding 170 with a currentof a selected frequency near the resonant frequency of the batterywinding 700, and then measure or otherwise determine the strength of thesignals received at each of the antennas 170. The power managementmodule 134 then compares the received signal strengths against referencevalues that have been specified for authentic batteries and stored inthe power management module 134.

The power management module 134 may drive the battery winding 700 atdifferent frequencies and determine the corresponding strengths of thesignals received at each of the antennas 170 at the differentfrequencies. Because each of the antennas 170 is sensitive to adifferent frequency range, the received signal strengths shouldgenerally differ between the two excitation frequencies. The powermanagement module 134 may authenticate the battery by driving thebattery winding 700 at a specific number of different excitationfrequencies, and comparing measured signal strengths against referencevalues. If a specified subset of the received signal strengths matchwith reference values, the battery 130 is authenticated.

The spectrum of electromagnetic radiation emitted by the battery winding130 also allows the power management module 134 to estimate the relativecondition of the battery 130. As illustrated above in FIGS. 12C and 12D,the effective impedance of the battery 130 drifts as the battery 130 isaged. The changing impedance of the battery 130 also causes acorresponding drift in the resonant frequency of the battery winding130. Accordingly, the spectrum of EMR emitted from the battery winding700 also changes characteristically as the battery 130 ages.

In some embodiments, the spectrum of EMR emitted by authentic batteriesat different intervals in the life cycle of the battery 130 isdetermined and stored in the power management module 134. By matchingthe characterized EMR spectrum of the battery 130 to one of thedetermined EMR spectrums corresponding to reference values for authenticbatteries of different ages, the power management module 134 may alsoestimate the relative condition of the battery 130. The relativecondition of the battery 130 may be estimated with or withoutauthenticating the battery 130 as described above.

Referring now to FIG. 14, there is illustrated a method 900 forauthenticating a battery, such as battery 130 (FIG. 4), for use with amobile communication device or other electronic device. The method 900may be performed by various components of the mobile device 100 (FIG.1), including the main processor 102 or the power management module 134shown in FIG. 4. Accordingly, the following description of method 900may be abbreviated for clarity. Further details of method 900 areprovided above with reference to various figures described previously.

At 905, optionally, a battery ID resistor included in the battery 130 isread to identify a type of the battery 130. Alternatively, if thebattery 130 includes an embedded processer, a battery ID value may berequested from the embedded processor at 905 to identify the type of thebattery 130. In some embodiments, a cryptographic authentication of thebattery 130 may also be performed at 905.

Due to the existence of third-party unauthorized or counterfeitbatteries, the identification or authentication of the battery 130performed at 905 through one or more of the above-described acts may notalways be reliable. For example, it may be possible to intercept thebattery ID value or some piece of cryptographic data used forauthentication of the battery 130, thereby making false identificationor authentication possible. To enhance battery authentication andsecurity, battery physical and electrical parameters may be useddiagnostically in various subsequent acts of method 900 to differentiatebetween authentic and inauthentic batteries without (or in addition to)the use of cryptographic data or other previous authenticationtechniques.

At 910, an electrical or electromagnetic response of the battery 130 dueto current flow in one or more windings or cells of a battery module ischaracterized or otherwise measured. To characterize the electrical orelectromagnetic response of the battery 130, one or more differentbattery quantities may be measured, such as the terminal voltage orcurrent of the battery module. In some embodiments, the voltage andcurrent measurements may be processed to calculate one or morederivative quantities used to characterize the electrical orelectromagnetic response of the battery 130.

Without limitation, the measured electrical or electromagnetic responseof the battery 130 may include any combination or one or more of thefollowing: charge capacity (FIGS. 5A and 5B), charge differential (FIGS.6A, 6B, 7, 8), voltage slump (FIGS. 9A and 9B), electrochemicalimpedance spectroscopy (FIGS. 10, 11, 12-12D), and electromagneticradiation (FIGS. 13A and 13B). Further specific details of each type ofelectrical or electromagnetic response are provided above with referenceto the figures noted respectively in parentheses.

At 915, the measured electrical or electromagnetic response is comparedwith a reference electrical or electromagnetic response for authenticbatteries. The reference electrical or electromagnetic response may bespecified and stored in the power management module 134, oralternatively the main processor 102, for comparison with the measuredelectrical or electromagnetic response. Each specified referenceresponse may be specific to a set of external conditions to which thebattery 130 may be subject, such as temperature and charge/dischargerate.

A corresponding reference response may also be specified and stored foreach of a plurality of different sets of conditions. The referenceelectrical or electromagnetic response compared against thecharacterized response may be the one specified for conditions mostclosely correlating to measured conditions of the battery 130. In someembodiments, a temperature sensor may be used to detect the currenttemperature of the battery 130 in order to selecting the appropriatereference response for comparison with the characterized response.

In some embodiments, the optionally read battery ID resistor oroptionally obtained battery ID value is also used at 915 to select oneof the reference electrical or electromagnetic responses that werespecified for authentic batteries. For example, reference electrical orelectromagnetic responses specified for batteries of the same type ofmodel as indicated by the battery ID resistor or ID value may beselected.

At 920, it is determined whether or not the characterized electrical orelectromagnetic response of the battery 130 matches the referenceelectrical or electromagnetic response. To make this determination, arange or other criterion of matching may be defined. If it is determinedthat the characterized and reference electrical or electromagneticresponses do not match, the flow of method acts proceeds to 930.

On the other hand, if it is determined at 920 that the characterized andreference electrical responses match, the flow of method acts proceedsto 925, in which a counter used to track the number of successfulmatches is incremented. Alternatively, some other suitable approach forkeeping track of the number of successful matches may be used at 925.The method then proceeds to 930.

At 930, it is determined whether a threshold minimum number ofcharacterized electrical or electromagnetic responses have matched withcorresponding reference responses. The threshold minimum number may bevariable, and may be based on the desired robustness and accuracy of themethod 900 and on the number of different types of electrical orelectromagnetic responses characterized. In some embodiments,authentication may be based on the matching of a single characterizedelectrical or electromagnetic response, for example selected from any ofthe above-noted types. The threshold minimum number of matches forsuccessful authentication would then be one.

By way of a further example, two or more different types of electricalor electromagnetic responses may be tested before the battery 130 willbe authenticated, which may then be based on successfully matching someminimum subset of the different characterized electrical orelectromagnetic responses. In some embodiments, each of the above-notedtypes of electrical or electromagnetic responses of the battery 130 maybe characterized, with authentication of the battery 130 requiring oneor more or all of the characterized electrical or electromagneticresponses to be successfully matched with corresponding referenceelectrical or electromagnetic responses.

If at 930, it is determined that the minimum number of electrical orelectromagnetic response characterized for the battery 130 has beensuccessfully matched with corresponding reference responses, the flow ofmethod acts proceeds to 935 where the battery 130 is authenticated.

However, if it is determined that fewer than the minimum number ofelectrical or electromagnetic responses characterized for the battery130 have been successfully matched with corresponding referenceresponses, the flow of method acts proceeds to 940 where it isdetermined if additional responses remain to be characterized.

If it is determined at 940 that no more electrical or electromagneticresponses of the battery 130 remain to be characterized (and fewer thanthe minimum number of characterized electrical or electromagneticresponses have been matched at 930), the flow of method acts proceeds to945 where the battery 130 is not authenticated. Should the battery 130not be authenticated, the main processor 102 may then initiate one ormore defined protocols or sequences, which may include providingfeedback to the user, controlling radio access in the mobile device 100,preventing the mobile device from operating or, for example, preventingthe battery 130 from charging.

However, if it is determined at 940 that additional electrical orelectromagnetic responses of the battery 130 remain to be characterized,the flow of method acts proceeds back to 910. The loop defined by 910through 940 may be repeated until either it is determined at 930 thatthe minimum number of characterized electrical or electromagneticresponses has been matched (resulting in authentication of the battery130) or it is determined at 940 that no more electrical orelectromagnetic responses of the battery 130 remain to be characterized(resulting in non-authentication of the battery 130).

Although not explicitly shown in FIG. 14, in addition or as analternative to performing authentication, and with suitablemodification, the method 900 may be adapted to estimate a relativecondition of the battery 130 (e.g. an age or state of health). Forexample, at 915, the characterized electrical or electromagneticresponse of the battery 130 may be compared against one or moredifferent reference electrical or electromagnetic responses forbatteries of the same type as battery 130 specified for different pointsin the lifetime of the battery 130. By determining which one of thereference electrical or electromagnetic responses most closely matchesthe characterized response, the relative condition of the battery 130may be estimated (e.g. according to the relative condition associatedwith the matched reference response). Optionally, the estimate of therelative condition may also be displayed to a user of the mobile device100 on a display, such as display 110 (FIG. 1), so that the user maytake suitable action.

Similar to authentication, an estimate of the relative condition of thebattery 130 may also be determined by comparing one or more differenttypes of electrical or electromagnetic responses. Accordingly, 920through 940 may be unchanged for estimating the relative condition ofthe battery 130. Of course, 935 would then correspond to successfulestimation of the relative condition, while 945 would correspond tounsuccessful estimation of the relative condition, for example becausethe characterized electrical or electromagnetic responses were tooinconsistent for successful estimation.

In variant embodiments, multiple estimates of the relative condition ofthe battery 130 may also be determined by comparing one or moredifferent types of electrical or electromagnetic responses in accordancewith any of the embodiments described herein, and then repeating thedetermination multiple times over some time period. In one aspect, dataidentifying the relative condition of the battery 130, and optionallyother data obtainable when determining the relative condition (e.g.generated curve or model data, the date or time when a given estimate ofthe relative condition was taken, etc.), can be logged by storing thedata in a memory store. FIG. 15 illustrates one example of a method ofdetermining an estimate of the relative condition of a battery inaccordance with at least one embodiment, with acts 960 and 970 beinggenerally analogous to acts 910 and 915 of FIG. 14 respectively.Accordingly, a history of determined estimates of the relative conditionof the battery 130 may be maintained. The mobile device 100 (e.g. powermanagement module 134) may be configured to log the data by storing thedata on the mobile device 100. The data may be additionally oralternatively stored on the battery 130 (e.g. battery memory 254). Datamay be partially stored on the mobile device 100, and partially storedon the battery 130. In variant implementations, the battery 130 (e.g.battery processor 252 or other module or circuitry) may be configured tolog the data by storing the data on the battery 130.

By providing logging functionality in combination with the features ofthe embodiments described herein, continuous monitoring of the battery130 may be more effectively implemented. This may enhance safety ofbattery use, or provide advance notice of a defective battery, forexample. For instance, if a series of estimates of the relativecondition of the battery 130 is taken over a period of time, the rate ofchange in the degradation of the state of health of the battery may bedetermined. If the rate of change of degradation exceeds a thresholdtolerance level (e.g. the battery is suffering wear over time much morequickly than what would be typical for a “normal” battery), then thismay be indicative that the battery 130 is defective or has suffereddamage. In one aspect, similar to the warranty prediction functionalitydescribed previously, a corresponding data message, signal or otherindicator may be automatically transmitted by the mobile device 100 to,for example, the manufacturer of the mobile device 100 or battery 130,to provide notice of this defect. If many batteries are experiencing thesame condition, this may provide the manufacturer with advanced notice,allowing the manufacturer to plan accordingly (e.g. prepare to deal witha recall or mass return of battery stock).

Moreover, data that has been logged when determining the relativecondition in a given instance may also be used in a subsequent instancefor more efficient processing. For example, if generated curve or modeldata has been previously stored for the battery 130, some of this datamay then be re-used to more quickly generate curves or other data whendetermining the current estimate of the relative condition of battery130 (or to authenticate the battery 130, or both).

The graphs depicted herein are provided for illustrative purposes to aidin the understanding of described embodiments, and are not necessarilyto scale. No representation is being made as to accuracy of the dataused to produce the graphs or the processes used to measure the data.

Some example embodiments have been described herein with reference tothe drawings and in terms of certain specific details to provide athorough comprehension of the described embodiments. However, it will beunderstood that the embodiments described herein may be practiced insome cases without one or more of the described aspects. In some places,description of well-known methods, procedures and components has beenomitted for convenience and to enhance clarity. It should also beunderstood that various modifications to the embodiments described andillustrated herein might be possible. The scope of the embodiments isthereby defined by the appended listing of claims.

1. An electronic device comprising: an interface for receiving a battery comprising a battery module for supplying power to the electronic device; and a power management module coupled to the battery and configured to: measure a voltage response of the battery due to current flow in the battery module; compare the measured voltage response of the battery to each of a plurality of reference voltage responses; and if the measured voltage response corresponds to each of the plurality of reference voltage responses, authenticate the battery for use with the electronic device.
 2. The device of claim 1, further comprising the battery.
 3. The device of claim 1, wherein the device comprises a mobile communication device.
 4. The device of claim 1, wherein each of the plurality of reference voltage responses comprises a reference voltage response of an authentic battery.
 5. The device of claim 4, wherein each of the reference voltage responses corresponding to a different relative condition of the authentic battery, and wherein the power management module is further configured to determine a relative condition of the battery by comparing the measured voltage response with each of the plurality of reference voltage responses.
 6. The device of claim 5, wherein the relative condition of the battery comprises at least one of an age or state of health of the battery.
 7. The device of claim 1, wherein the power management module is configured to: measure a plurality of voltage responses of the battery due to current flow in the battery module; compare each of the measured plurality of voltage responses of the battery with a corresponding one of the plurality of reference voltage responses; and if a minimum number of the measured plurality of voltage responses corresponds to a threshold number of the plurality of reference voltage responses, authenticate the battery for use with the electronic device.
 8. The device of claim 1, wherein the power management module is configured to measure the voltage response of the battery based on a plurality of AC voltages measured across the battery module, each measured AC voltage measured for a corresponding AC excitation current of a different frequency supplied to the battery module.
 9. The device of claim 1, wherein the power management module is configured to measure the voltage response of the battery based on a voltage slump measured across the battery module during pulsed discharging of the battery module.
 10. The device of claim 1, wherein the power management module is configured to measure the voltage response of the battery based on a charge differential relation of the battery module, the charge differential relation representing a rate of change of a charge capacity of the battery module with respect to a terminal voltage of the battery module.
 11. The device of claim 1, wherein the power management module is configured to measure the voltage response of the battery based on a charge capacity relation of the battery module, the charge capacity relation representing stored charge in the battery module as a function of a terminal voltage of the battery module.
 12. A method for authenticating a battery for use with an electronic device, the battery comprising a battery module for supplying power to the electronic device, the method comprising: measuring a voltage response of the battery due to current flow in the battery module; comparing the measured voltage response of the battery to each of a plurality of reference voltage responses; and if the measured voltage response corresponds to each of the plurality of reference voltage responses, authenticating the battery for use with the electronic device.
 13. The method of claim 12, wherein the device comprises a mobile communication device.
 14. The method of claim 12, wherein each of the plurality of reference voltage responses comprises a reference voltage response of an authentic battery.
 15. The method of claim 14, wherein each of the expected voltage responses corresponding to a different relative condition of the authentic battery, and wherein the method further comprises determining a relative condition of the battery by comparing the measured voltage response with each of the plurality of reference voltage responses.
 16. The method of claim 15, wherein the relative condition of the battery comprises at least one of an age or state of health of the battery.
 17. The method of claim 12, further comprising: measuring a plurality of voltage responses of the battery due to current flow in the battery module; comparing each of the measured plurality of voltage responses of the battery to a corresponding one of the plurality of reference voltage responses; and if a minimum number of the measured plurality of voltage responses corresponds to a threshold number of the plurality of the reference voltage responses, authenticating the battery for use with the electronic device.
 18. The method of claim 12, wherein the measuring the voltage response of the battery is based on a plurality of AC voltages measured across the battery module, each measured AC voltage measured for a corresponding AC excitation current of a different frequency supplied to the battery module.
 19. The method of claim 12, wherein the measuring the voltage response of the battery is based on a voltage slump measured across the battery module during pulsed discharging of the battery module.
 20. The method of claim 12, wherein the measuring the voltage response of the battery is based on a charge differential relation of the battery module, the charge differential relation representing a rate of change of a charge capacity of the battery module with respect to a terminal voltage of the battery module.
 21. The method of claim 12, wherein the measuring the voltage response of the battery is based on a charge capacity relation of the battery module, the charge capacity relation representing stored charge in the battery module as a function of a terminal voltage of the battery module.
 22. A power management module for an electronic device supplied with power from a battery comprising a battery module, the power management module comprising a processor and memory coupled to the processor storing instructions when executed for programming the processor, the instructions comprising: measuring a voltage response of the battery due to current flow in the battery module; comparing the measured voltage response of the battery to each of a plurality of reference voltage responses; and if the measured voltage response corresponds to each of the plurality of reference voltage responses, authenticating the battery for use with the electronic device. 